(5) Investment in Sunrise Energy (Details) - Condensed Balance Sheet (Sunrise Energy, USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Sunrise Energy
(5) Investment in Sunrise Energy (Details) - Condensed Balance Sheet [Line Items]
Current assets	$ 2,506
Oil and gas properties, net	6,842
	9,348
Total liabilities	727
Members' capital	8,621
	$ 9,348